One type of agricultural machine is an agricultural combine. Agricultural combines are engine powered machines that harvest, thresh, separate and clean an agricultural crop.
An agricultural combine typically is equipped to accommodate a removable harvesting platform. One such harvesting platform is provided with an elongated cutter bar assembly for cutting a standing crop. The cutter bar assembly includes a steel support bar, a series of sickle guards, a knifeback, a series of knives and a series of hold-down clips. The sickle guards are mounted to the support bar. Each of the guards is provided with a channel in which the knifeback is slideably positioned. In addition, each guard is provided with a slot having ledger plates into which the knives are slideably positioned. A series of triangular knives are bolted to the knifeback. The hold-down clips are bolted to the support bar and extend forward over the knifeback into contact with the knives for holding the knives against the ledge plates of the sickle guards. The cutting edges of the knives and the ledger plates cooperate to shear the standing crop as the knifeback and the attached series of knives move in a reciprocating manner.
Farmers may rotate between varieties of crops. For example, one may follow a corn crop the next year with a no-till soybean crop. With the advent of drought resistant and herbicide tolerant corn species, however, it is possible that some of the corn stalks may still be present in the field at the time of harvesting the soybean crop. Sometimes, corn stalks and/or weed stems of large diameter will partially enter the cutter bar assembly without being cut, resulting in the plugging of the cutter bar assembly, and which in turn may result in crop loss and equipment damage.